Unilateral C-1 posterior arch screws and C-2 laminar screws combined with a 1-side C1–2 pedicle screw system as salvage fixation for atlantoaxial instability

作者：Guoxin Jin, Huan Wang · 发表于：Journal of Neurosurgery Spine · 年份：2015 · DOI：10.3171/2015.4.spine14517 · 被引用次数：20 · 研究领域：Spinal Fractures and Fixation Techniques、Spine and Intervertebral Disc Pathology、Neurosurgical Procedures and Complications

OBJECT Atlantoaxial instability often requires surgery, and the current methods for fixation pose some risk to vascular and neurological tissues. Thus, new effective and safer methods are needed for salvage operations. This study sought to assess unilateral C-1 posterior arch screws (PASs) and C-2 laminar screws (LSs) combined with 1-side C1-2 pedicle screws (PSs) for posterior C1-2 fixation using biomechanical testing with bilateral C1-2 PSs in a cadaveric model. METHODS Six fresh ligamentous human cervical spines were evaluated for their biomechanics. The cadaveric specimens were tested in their intact condition, stabilization after injury, and after injury at 1.5 Nm of pure moment in 6 directions. The 3 groups tested were bilateral C1-2 PSs (Group A); left side C1-2 PSs with an ipsilateral C-1 PAS + C-2 laminar screw (Group B); and left side C1-2 PSs with a contralateral C-1 PAS + C-2 LS (Group C). During the testing, angular motion was measured using a motion capture platform. Data were recorded, and statistical analyses were performed. RESULTS Biomechanical testing showed that there was no significant difference among the stabilities of these fixation systems in flexion-extension and rotation control. In left lateral bending, the bilateral C1-2 PS group decreased flexibility by 71.9% compared with the intact condition, the unilateral C1-2 PS and ipsilateral PAS+LS group decreased flexibility by 77.6%, and the unilateral C1-2 PS and contralateral PAS+LS group by 70.0%. Ea...